Computed Tomography (CT) Angiography is a method for imaging the vascular system that combines innovative image processing with the use of new slip-ring CT scanners. This method allows for the rapid acquisition of large volumes of CT data during the arterial phase of a peripheral intravenous contrast injection. The goals of the proposed project would be to develop the algorithms and techniques that exploit this volume-scan CT technology to produce three-dimensional CT angiograms that could substitute for more costly and invasive intra-arterial angiograms in specific applications within the abdomen. The technical developments would include computer algorithms for production of two dimensional (2-D) angiograms from 3-D CT data, contrast bolus timing techniques, minimization of artifacts from motion and bolus timing inaccuracies, and image processing strategies for segmentation of complex vascular structures from volumes containing bones and soft tissue. Clinical studies would be conducted to assess the diagnostic accuracy of the method in renal artery stenosis and in abdominal aortic aneurysms. Upon the successful completion of this project, the applicants projected that the method would be a lower cost, lower risk alternative to diagnostic arteriography.